ok well thats shorts then for whatever reasons ......

it takes quite a bit of sustained current to actually melt the junction at low voltage. whereas for smaller active area at much higher voltage these are quite easy to wreck.

im surprised to hear anybody is repairing old consumer electroncs. surely this is uneconomic ?

That doesn't really make sense.

When forward biased the voltage across the diode will be determined by the current* through it irrespective of the supply voltage, it doesn't matter whether the supply is 1000V or 50V. Of course at a higher voltage it is easier to get a higher peak current for a reactive load that can cause a problem but that isn't what you posted which seemed to be treating the diode as if higher supply voltages put more voltage across the diode in forward bias.

In reverse bias the only current is leakage which will be determined by the voltage* not what current the load is taking, the diode needs to be capable of handling the voltage.

*Temperature also affects these but is not relevant to the main point.

As bobcar says, total nonsense


Not when they weren't old

And even now there's a certain amount of historical interest - but basically just a comment that rectifier failure is commonplace, and has been for MANY decades (and no sense at all in the bizarre Sky mention?).